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Load Online Observations From MPC And JPL

This guide shows how to fetch online observations for 2025 BC10 from MPC and JPL and save them to a local ADES PSV file.

Prerequisites

  • Activate the project environment described in Installation.
  • This guide requires internet access to the MPC Observations API and the JPL small-body radar API.
  • Online results can change. The output below is one reference run from 2026-04-23.

1. Fetch online observations

Use load_online_observations(...) with a designation or name accepted by MPC. The same value is also sent to the JPL radar service.

from difforb.astrometry import load_online_observations

obs = load_online_observations("2025 BC10")

print("NAME", obs.name)
print("N_OBS", len(obs))
print("N_OPTICAL", obs.num_optical)
print("N_RADAR", obs.num_radar)
print("T_START", obs.t_start.ut.iso_string)
print("T_END", obs.t_end.ut.iso_string)
Output
NAME 2025 BC10
N_OBS 807
N_OPTICAL 799
N_RADAR 8
T_START 2025-01-28 13:31:33.500
T_END 2025-04-06 06:39:50.960

2. Save the result to a local PSV file

Pass save_path= to save the fetched observations as ADES pipe-separated values (PSV). The path must use the .psv suffix.

from pathlib import Path

from difforb.astrometry import load_online_observations

saved_path = Path("/tmp/2025bc10-online-guide.psv")
obs = load_online_observations("2025 BC10", save_path=str(saved_path))

print("FILE_EXISTS", saved_path.exists())
print("SUFFIX", saved_path.suffix)
print("N_OBS", len(obs))
Output
FILE_EXISTS True
SUFFIX .psv
N_OBS 807

The next three guides use this same PSV file.

Common Mistakes

  • The online data can change, so the counts and date bounds can change too.
  • save_path= requires a .psv filename.
  • The returned ObservationData holds data for one target only.

Next Steps